Global warming is a rise in average global temperature. Your question can be restated as: What other factors can contribute to the rising in temperatures besides rise in average global temperature? This is akin to asking what factors contribute to daybreak besides sunrise, and is probably why no one has felt compelled to jump into the conversation. Had you written this question, you might have stimulated more conversation:What other factors can contribute to the rising in temperatures besides anthropogenic carbon emissions?

This is not a topic I am inclined to discuss today, so good luck with the conversational gambit.